Project Summary The social, geographic, and environmental context of a person in treatment for alcohol use can impact their risk of using alcohol and experiencing relapse. This study explores novel methods to assess how individuals entering outpatient treatment for alcohol-related problems interact within social networks and environmental contexts and the impact these contexts have on relapse and treatment engagement. Despite increases in the use of technology in public health research, public health remains woefully behind other fields (e.g., marketing) in using social technologies. Smartphone technologies can allow us to develop methods consistent with precision health that can assess real-time social and geographic contributors to alcohol use and relapse. This project will use two primary methods for examining geographic and social risks related to relapse: activity space assessments and context-aware experience sampling. With the use of activity space assessments (a method that assesses where people go, who they go with, and what they do at the locations) we will learn where individuals spend time and with whom they engage in risky behaviors. With context aware experience sampling, a technique that assesses participants multiple times a day based on contextual factors (e.g., GPS location), we can capture real-world and contextual influences on behavior as close to the occurrence of the behavior as possible. In other words, we can capture behavior, social interactions, and geographic context in real time and real world settings and assess how these interactions influence or accelerate relapse. We will recruit 400 adults from substance use treatment facilities in Northeast Georgia and New Haven, CT as they enter formal treatment for alcohol-related problems. At baseline, all participants will complete a social network assessment and an activity space assessment. These assessments will be used to guide the real-time context- aware experience sampling of interpersonal mechanisms of social and location environment. Further, participants will complete interviews about their alcohol use and other related behaviors for 12 months, which will further be confirmed through alcohol testing. We anticipate using findings from this research to inform the development of a cell-phone-based relapse prevention intervention with social network and geographic- triggered recovery support tools for adults completing treatment for alcohol-related problems.